Learn how to optimize First Contentful Paint below 1.8s at p75. Covers TTFB reduction, render-blocking CSS, web fonts, 103 Early Hints, and Speculation Rules prerender with production code.
Learn how RFC 9211's Cache-Status header exposes hits, misses, forwards, and coalesced requests across your CDN chain. Includes vendor mapping and TTFB attribution patterns.
Break down Time to First Byte into named backend phases with the Server-Timing header. Includes syntax, CORS gotchas, Node/Workers/nginx examples, and RUM integration.
How to use the stale-while-revalidate Cache-Control directive to serve cached responses instantly while revalidating in the background. RFC 5861 recipes, CDN support in 2026, and footguns to avoid.
HTTP 103 Early Hints lets servers preload critical resources during backend think-time, cutting LCP by 100-400ms. A practical 2026 guide for Cloudflare, Fastly, and Node.js origins.
HTTP/3 over QUIC removes TCP head-of-line blocking and cuts mobile load times 20-60%. Practical setup for Nginx, Caddy, and Cloudflare with a rollout plan.